DFG Deutsche Forschungsgemeinschaft

Chemistry and Physics of Macromolecules

Final Report of the Sonderforschungsbereich "Chemie und Physik der Makromoleküle" 1969-1987

Edited by Erhard W. Fischer, Rolf С Schulz, and Hans Sillescu

Sonderforschungsbereiche

Contents

1 General Introduction 1 1.1 Polymer Science in the Federal Republic of Germany . . . 1 1.2 Objectives and Developments of the

Sonderforschungsbereich 41 2 1.3 Topics and Results 4 1.3.1 Pathways to New Polymers 4 1.3.2 Kinetics, Mechanisms, and Polymer Characterization . . . 7 1.3.3 New Methods in Polymer Physics 8 1.3.4 Conformation and Interaction of Macromolecules in

Polymer Systems 8 1.3.5 Macromolecules in Motion 9 1.3.6 Cooperative Phenomena in Polymers 10 1.4 References 11

2 From Oligonuclear Phenolic Compounds to Calixarenes . . 13 Volker Böhmer and Hermann Kämmerer

2.1 Introduction 13 2.2 Synthesis of Structurally Uniform Oligomers 14 2.2.1 General Principles, Protective Groups 14 2.2.2 Linear Oligomers 15 2.2.3 Cyclic Oligomers, Calixarenes 16 2.2.4 Chemical Modifications 19 2.2.5 Synthetic Matrix Reactions 21 2.3 Phenolic Oligomers in the Solid State 23 2.3.1 Cyclic Oligomers 23 2.3.2 Linear Compounds 25 2.4 Reactions and Properties in Solution 26 2.4.1 Spectroscopic Studies 26 2.4.2 Acidity, pK-Values 27

VII

Contents

2.4.3 Kinetic Studies 29 2.4.4 Complexation of Cations, Host-Guest Interactions . . . . 30 2.5 Concluding Remarks 32 2.6 References 32

3 Synthesis of Monodisperse Oligomers 39 Manfred Rothe

3.1 Introduction: Importance of Oligomers 39 3.2 Synthesis of Monodisperse Oligomers 41 3.2.1 Oligomer Formation 41 3.2.2 Principles of Oligomer Synthesis 42 3.2.3 Synthesis of Monodisperse Oligoamides, Homo­

Oligopeptides, and Sequential Oligopeptides 44 3.2.3.1 Linear Oligoamides of the Nylon Type and Collagen

Models 44 3.2.3.2 Cyclic Oligoamides of the Nylon Type 50 3.3 Physical Properties of Synthesized Monodisperse

Oligoamides and Oligopeptides 53 3.3.1 Chain-Length Dependence of the Conformation of Linear

Oligo-L-Prolines 53 3.3.2 Ring-Size Dependence of Physical Properties 56 3.4 Outlook 58 3.5 References 58

4 Telechelic Oligomers 61 Walter Heitz

4.1 Introduction 61 4.2 Telechelics by Cationic Polymerization 63 4.3 Telechelics by Anionic Polymerization 70 4.4 Telechelics by Radical Polymerization 71 4.4.1 Mechanistic Aspects 72 4.4.1.1 Elementary Steps 72 4.4.1.2 Dead End Polymerization 74 4.4.1.3 The Initiator 78 4.4.1.4 Monomers 81 4.5 Telechelics by Metal Catalyzed Reactions 90 4.6 Telechelic Hard Segments 91 4.7 References 93

VIII

Contents

Cyclic and Macrocyclic Compounds 97 Hartwig Höcker and Rolf C. Schulz Introduction 97 Ring-Chain Equilibria 98 Cycloolefins and Cycloparaffins Obtained by Metathesis Polymerization of Cyclomonoolefins 98 Properties of Cycloolefins and Cycloparaffins 102 Cyclic Oligomers of Cycloacetals 104 Synthesis of Cyclophanes via Polycombination Reaction Induced by Electron Transfer to Divinylidene Compounds . 107 Macrocyclic Polystyrene 109 Concluding Remarks 113 References 113

Kinetics of Copolymerization 115 Dietrich Braun and Wojciech K. Czerwinski Introduction 115 Experimental Methods 116 Binary Copolymerization 117

1 Classical Rate Model 117 2 Model of Diffusion Controlled Termination 118 3 Penultimate Model 119 4 Supplementary Concepts 120 5 Experimental Results 121

Ternary Copolymerization 127 1 Classical Rate Model for Three Homopolymerizable

Monomers 128 2 Model of Diffusion Controlled Termination 131 3 Experimental Results 133

Conclusions 135 References 137

Free Radical Polymerization: From Spontaneous Initiation up to the Glass Transition State 141 Günther Meyerhoff, Günter V. Schulz, and Jürgen Lingnau Introduction 141 Experimental Approach 142

1 Kinetic Experiments 142 2 Identification and Kinetics of Formation of Side Products . 143 3 Determination of Molecular Weight Distributions . . . . 143

Spontaneous Polymerization 148 1 The Spontaneous Polymerization of Styrene 149

2 The Spontaneous Polymerization of Methacrylates . . . . 150 2.1 General Aspects 150 2.2 The Oligomers 151 2.3 Solvent Effects 153 2.4 Other Acrylates 155 2.5 "Chemical Simulation" 155 2.6 The Mechanism and its Formal Description 157

Kinetics for Medium and High Conversions 159 1 Kinetics of the Initiated Polymerization below the Onset

of the Gel Effect 159 2 Kinetics of the Initiated Polymerization beyond the Onset

of the Gel Effect up to the Glass Transition Point . . . . 160 3 Results of the Polymerization Experiments 161 4 Rate Constants and Diffusion Mechanisms 164 5 Chain Length and Conversion 165

Conclusion 166 References 166

Kinetics and Mechanisms of Anionic and Group Transfer Polymerization 171 Axel H. E. Müller, Hartwig Höcker, and Günter V. Schulz Introduction 171 Polymerization of Styrene 173

1 Ions and Ion Pairs 173 2 Contact and Solvent-Separated Ion Pairs 176

Polymerization of Acrylic Monomers 179 1 Potential Problems 179 2 Methyl Methacrylate 181 3 Other Methacrylates 191 3.1 Homopolymerization 191 3.2 Copolymerization 192 4 Polymerization in Non-Polar Solvents 194

Group Transfer Polymerization of Methacrylates 196 1 Introduction 196 2 General Considerations 197 3 Kinetic Investigations 199 4 Control of Molecular Weight Distribution 202

References 204

Contents

9 Molecular Engineering of Liquid Crystalline Polymers . .211 Helmut Ringsdorf, Ingrid Voigt-Martin, Joachim Wendorff, Renate Wüstefeld, and Rudolf Zentel

9.1 Introduction: Self Organizing Systems 211 9.2 Molecular Architecture of Liquid Crystalline Polymers . . 212 9.2.1 Liquid Crystalline Polymers with Rod-like Mesogens . . . 218 9.2.1.1 Synthesis and Structure-Property Relations of LC Side

Group Polymers 218 9.2.1.2 Synthesis and Structure-Property Relationships of Main

Chain Polymers 224 9.2.1.3 Molecular Engineering of LC-Polymers: Side Group and

Main Chain LC Systems 224 9.2.2 Liquid Crystalline Polymers with Disc-like Mesogens . . . 228 9.2.2.1 Polymers with Discotic Phases 231 9.2.2.2 Polymers with Sanidic Phases 233 9.2.3 Functionalized Liquid Crystalline Polymers 237 9.2.3.1 Dye Containing Polymers 237 9.2.3.2 Photosensitive Liquid Crystalline Polymers 238 9.2.3.3 Liquid Crystalline Elastomers 242 9.3 Molecular Architecture and Physical Properties 247 9.3.1 The Amorphous, Crystalline and Liquid Crystalline

State of Matter 247 9.3.2 Fluctuations in Liquid Crystalline Polymers 248 9.3.2.1 Defining Fluctuations 248 9.3.2.2 Kerr Relaxation Studies on Orientational Fluctuations . . 249 9.3.2.3 Small Angle X-Ray Scattering Studies on Orientational

Correlations in Side Group Polymers 252 9.3.3 High Resolution Electronmicroscopy as a Tool for

Visualizing Smectic Structures 253 9.3.3.1 Introduction 253 9.3.3.2 Sample Preparation 254 9.3.3.3 Structural Information Obtained by Electron Microscopy . 254 9.3.3.4 Image Analysis and Processing 260 9.3.3.5 Conclusion 262 9.4 References 262

10 Thermodynamics and Rheology of Polymer Solutions . . . 273 Bernhard A. Wolf

10.1 Pressure, the Neglected Variable 274 10.1.1 Thermodynamics 274 10.1.1.1 Pressure Dependence of Polymer Solubility 274 10.1.1.2 Pressure Dependence of Interaction Parameters 276 10.1.2 Viscometry 277

Contents

10.1.2.1 Intrinsic Viscosities 277 10.1.2.2 Activation Volumes 278 10.2 On the Role of Chain Length 279 10.2.1 Development of Incompatibility 280 10.2.1.1 Experiments with Oligomers 280 10.2.1.2 Solubility Parameter Theory 280 10.2.2 Molecular Weight Dependence of Pair Interactions . . . . 282 10.2.2.1 Theoretical Concept 282 10.2.2.2 Experimental Results and Discussion 283 10.3 Interrelation of Thermodynamic and Rheological Properties 286 10.3.1 Flow under Different Thermodynamic Conditions . . . . 286 10.3.1.1 The Pull-along Effect 286 10.3.1.2 Thermoreversible Gelation 287 10.3.2 Phase Separation of Flowing Polymer Solutions 289 10.3.2.1 Experimental Results 289 10.3.2.2 Theory and Discussion 289 10.4 Outlook 292 10.5 References 293

11 Polymer Diffusion as Studied by Holographic Grating Techniques 295 Hans Sillescu

11.1 Introduction 295 11.2 Physical Principles and Experimental Aspects 296 11.2.1 Hologram Formation 296 11.2.2 Hologram Reading by Forced Rayleigh Scattering . . . . 297 11.2.3 Analysis of Diffusion Experiments 299 11.2.4 Photo-Labeling and Sample Preparation 300 11.3 Applications 302 11.3.1 Diffusion of Polymer Chains by Reptation and other

Transport Mechanisms 302 11.3.2 Diffusion of Polymer Rings, Microgels, and Stars . . . . 305 11.3.3 Diffusion of Monomer Dyes at the Glass Transition of

Amorphous Polymers 307 11.4 References 310

12 Deuteron NMR. A New Tool for Investigating Order and Dynamics in Polymers 313 Hans Wolfgang Spiess and Hans Sillescu

12.1 Introduction 313 12.2 Techniques 314 12.2.1 Dynamics 314

XII

Contents

12.2.1.1 Slow Motion and Solid Echo Spectra 314 12.2.1.2 Spin-Alignment 319 12.2.1.3 Spin Lattice Relaxation 320 12.2.1.4 Distribution of Correlation Times 321 12.2.2 Order 322 12.2.2.1 Orientational Distribution 322 12.2.2.2 Expansion in Terms of Spherical Functions 324 12.2.2.3 13C-MAS-NMR 326 12.3 Experimental Examples 329 12.3.1 Dynamics 329 12.3.1.1 Chain Motion in Linear Polyethylene 329 12.3.1.2 Molecular Motion and Mechanical Properties of

Polycarbonate 330 12.3.1.3 Molecular Motion in Interfacial Regions of Segmented

Polyurethanes 332 12.3.1.4 Motion of Mesogens in Liquid Crystalline Polymers . . . 333 12.3.1.5 Mobility of Lipid Chains in Polymer Model Membranes . . 335 12.3.2 Order 337 12.3.2.1 Molecular Order in Liquid Christalline Polymers 337 12.3.2.2 Drawn Fibres of Poly(ethyleneterephthalate) (PET) . . .339 12.3.3 Overview of the 2H-NMR in Polymers 341 12.4 New Developments: Two-dimensional 2H-NMR 341 12.5 References 344

13 The Kerr Effect as Applied to the Investigation of Polymers 349 Bernd-J. Jungnickel and Joachim H. Wendorff

13.1 Introduction 349 13.2 Fundamentals 350 13.2.1 Experimental Setup and Procedure 350 13.2.2 Basic Theoretical Relations 352 13.2.3 Information Content of the Effect 356 13.3 Glassy-Amorphous Polymers 357 13.3.1 Theoretical Considerations 358 13.3.2 Experimental Investigations and Results 361 13.3.3 Discussion 364 13.4 Liquid Crystalline Polymers 365 13.4.1 Introduction: Pretransitional Effects 365 13.4.2 Kerr Effect and Order Parameter Fluctuations 366 13.4.2.1 Static Properties 366 13.4.2.2 Dynamical Properties 367 13.4.3 Kerr Effect Studies on Liquid Crystalline Side Chain

Polymers 368 13.5 References 374

XIII

Contents

14 Concentration Fluctuations and Kinetics of Phase Separation in Polymer Blends 377 Gert Strobl i

14.1 Introduction 377 14.2 Theory 378 14.2.1 Phase Behaviour of Polymer Blends 378 14.2.2 Concentration Fluctuations in Thermal Equilibrium . . . . 381 14.2.3 Kinetics of Unmixing 382 14.3 Small Angle X-Ray Scattering Studies 385 14.3.1 Polystyrene/Poly(styrene-co-bromostyrene) Blends . . . . 385 14.3.2 Static Structure Factors 386 14.3.3 Relaxation after T-Jumps within the One-Phase Region . . 389 14.3.4 Kinetics of Spinodal Decomposition 393 14.4 References 395

15 Collective Dynamics in Polymeric Liquids as Measured by Quasi-elastic Light- and Neutron Scattering 397 Erhard W. Fischer, Bernd Ewen, and Gerhard Meier

15.1 The Dynamics of Density Fluctuations as Measured by Quasi-elastic Light Scattering 397

15.1.1 The Theory of Light Scattering from an Isotropic Viscoelastic Medium 397

15.1.2 The Comparison between Theory and Experiment . . . . 403 15.1.3 Data Evaluation of PCS Results 404 15.1.4 Connection between Molecular and Collective Dynamics . 406 15.1.5 Separation of Primary and Secondary Relaxation Processes

in Polymethacrylates 411 15.2 The Dynamics of Concentration Fluctuations in a

Compatible Binary Polymer Blend 414 15.3 Rayleigh-Brillouin Spectroscopy of Structurally Relaxing

Liquids 420 15.3.1 Inelastic Scattering from a Liquid Consisting of Linear

Chain Molecules 420 15.3.2 Hypersonic Relaxation in a Viscoelastic Non-polymeric

Liquid 422 15.4 Collective Fluctuations of Chain Segments in Dense Liquid

Polymer Systems as Studied by Neutron Spin Echo Spectroscopy 424

15.4.1 Neutron Spin Echo 424 15.4.2 Segmental Diffusion in Polymer Melts and Concentrated

Solutions 426 15.4.3 Unattached Polymer Chains in Permanent Networks . . . 434 15.4.4 Diffusive Motion of Cross-links 435

XIV

Contents

15.5 Conclusions 439 15.6 References 441

16 Structure and Properties of Semicrystalline Polymers . . . 445 Erhard W. Fischer, Manfred Stamm, and Ingrid G. Voigt-Martin

16.1 Introduction 445 16.2 Morphology of Semicrystalline Polymers 446 16.2.1 Comparison of Different Techniques 446 16.2.2 Small Angle X-Ray Scattering (SAXS) 446 16.2.3 Electron Microscopy (EM) 448 16.3 Chain Conformation in the Crystalline State 455 16.3.1 General Considerations 455 16.3.2 Experimental Techniques 458 16.3.3 Small Angle Neutron Scattering (SANS) 460 16.4 Crystallization and Melting 466 16.4.1 Investigation of the Crystallization and Melting Process . . 466 16.4.2 Stress Induced Crystallization 468 16.5 Blockcopolymers with Crystalline Blocks 471 16.5.1 Morphology and Models 471 16.5.2 SAXS and SANS Investigations 472 16.6 Conclusions 473 16.7 References 474

17 Chain Conformation and Local Order in Amorphous Polymers 477 Erhard W. Fischer and Ingrid G. Voigt-Martin

17.X Introduction 477 17.2 Chain Conformation 479 17.3 Short-range Positional Order 484 17.4 Direct Structural Observation 488 17.5 Orientational Order 490 17.6 Density Fluctuations 494 17.7 References 496

18 Theory of Dense Polymer Systems 499 Kurt Binder, Kurt Kremer, Ingeborg Carmesin, and Alia Sariban

18.1 Introduction 500 18.2 Mean Field Theories of Polymer Mixtures 501 18.2.1 Spinodal Decomposition of Polymer Alloys 502

XV

Contents

18.2.2 Effects of Polydispersity and Shear 505 18.2.3 Wetting of Polymer Mixtures 508 18.3 Scaling and Computer Simulation Investigations 511 18.3.1 Phase Separation of A-chain - B-chain - Solvent Systems .512 18.3.2 Dynamics of a Polymer in a Tube: Test of the Reptation

Concept 519 18.3.3 Molecular Dynamics Simulation of a Polymer Melt . . . . 523 18.4 Conclusions 526 18.5 References 528

Appendix: Documentation of the Sonderforschungsbereich 41 . . . . 533

XVI

DFG Deutsche Forschungsgemeinschaft

Chemistry and Physics of Macromolecules

Final Report of the Sonderforschungsbereich "Chemie und Physik der Makromoleküle" 1969-1987

Edited by Erhard W. Fischer, Rolf C. Schulz, and Hans Sillescu

Sonderforschungsbereiche

Contents

1 General Introduction 1 1.1 Polymer Science in the Federal Republic of Germany . . . 1 1.2 Objectives and Developments of the

Sonderforschungsbereich 41 2 1.3 Topics and Results 4 1.3.1 Pathways to New Polymers 4 1.3.2 Kinetics, Mechanisms, and Polymer Characterization . . . 7 1.3.3 New Methods in Polymer Physics 8 1.3.4 Conformation and Interaction of Macromolecules in

Polymer Systems 8 1.3.5 Macromolecules in Motion 9 1.3.6 Cooperative Phenomena in Polymers 10 1.4 References 11

2 From Oligonuclear Phenolic Compounds to Calixarenes . . 13 Volker Böhmer and Hermann Kämmerer

2.1 Introduction 13 2.2 Synthesis of Structurally Uniform Oligomers 14 2.2.1 General Principles, Protective Groups 14 2.2.2 Linear Oligomers 15 2.2.3 Cyclic Oligomers, Calixarenes 16 2.2.4 Chemical Modifications 19 2.2.5 Synthetic Matrix Reactions 21 2.3 Phenolic Oligomers in the Solid State 23 2.3.1 Cyclic Oligomers 23 2.3.2 Linear Compounds 25 2.4 Reactions and Properties in Solution 26 2.4.1 Spectroscopic Studies 26 2.4.2 Acidity, pK-Values 27

Contents

2.4.3 Kinetic Studies 29 2.4.4 Complexation of Cations, Host-Guest Interactions . . . . 30 2.5 Concluding Remarks 32 2.6 References 32

3 Synthesis of Monodisperse Oligomers 39 Manfred Rothe

3.1 Introduction: Importance of Oligomers 39 3.2 Synthesis of Monodisperse Oligomers 41 3.2.1 Oligomer Formation 41 3.2.2 Principles of Oligomer Synthesis 42 3.2.3 Synthesis of Monodisperse Oligoamides, Homo­

Oligopeptides, and Sequential Oligopeptides 44 3.2.3.1 Linear Oligoamides of the Nylon Type and Collagen

Models 44 3.2.3.2 Cyclic Oligoamides of the Nylon Type 50 3.3 Physical Properties of Synthesized Monodisperse

Oligoamides and Oligopeptides 53 3.3.1 Chain-Length Dependence of the Conformation of Linear

Oligo-L-Prolines 53 3.3.2 Ring-Size Dependence of Physical Properties 56 3.4 Outlook 58 3.5 References 58

4 Telechelic Oligomers 61 Walter Heitz

4.1 Introduction 61 4.2 Telechelics by Cationic Polymerization 63 4.3 Telechelics by Anionic Polymerization 70 4.4 Telechelics by Radical Polymerization 71 4.4.1 Mechanistic Aspects 72 4.4.1.1 Elementary Steps 72 4.4.1.2 Dead End Polymerization 74 4.4.1.3 The Initiator 78 4.4.1.4 Monomers 81 4.5 Telechelics by Metal Catalyzed Reactions 90 4.6 Telechelic Hard Segments 91 4.7 References 93

VIII

Cyclic and Macrocyclic Compounds 97 Hartwig Höcker and Rolf C. Schulz Introduction 97 Ring-Chain Equilibria 98 Cycloolefins and Cycloparaffins Obtained by Metathesis Polymerization of Cyclomonoolefins 98 Properties of Cycloolefins and Cycloparaffins 102 Cyclic Oligomers of Cycloacetals 104 Synthesis of Cyclophanes via Polycombination Reaction Induced by Electron Transfer to Divinylidene Compounds . 107 Macrocyclic Polystyrene 109 Concluding Remarks 113 References 113

Kinetics of Copolymerization 115 Dietrich Braun and Wojciech K. Czerwinski Introduction 115 Experimental Methods 116 Binary Copolymerization 117

1 Classical Rate Model 117 2 Model of Diffusion Controlled Termination 118 3 Penultimate Model 119 4 Supplementary Concepts 120 5 Experimental Results 121

Ternary Copolymerization 127 1 Classical Rate Model for Three Homopolymerizable

Monomers 128 2 Model of Diffusion Controlled Termination 131 3 Experimental Results 133

Conclusions 135 References 137

Free Radical Polymerization: From Spontaneous Initiation up to the Glass Transition State 141 Günther Meyerhoff, Günter V. Schulz, and Jürgen Lingnau Introduction 141 Experimental Approach 142

1 Kinetic Experiments 142 2 Identification and Kinetics of Formation of Side Products . 143 3 Determination of Molecular Weight Distributions . . . . 143

Spontaneous Polymerization 148 1 The Spontaneous Polymerization of Styrene 149

2 The Spontaneous Polymerization of Methacrylates . . . . 150 2.1 General Aspects 150 2.2 The Oligomers 151 2.3 Solvent Effects 153 2.4 Other Acrylates 155 2.5 "Chemical Simulation" 155 2.6 The Mechanism and its Formal Description 157

Kinetics for Medium and High Conversions 159 1 Kinetics of the Initiated Polymerization below the Onset

of the Gel Effect 159 2 Kinetics of the Initiated Polymerization beyond the Onset

of the Gel Effect up to the Glass Transition Point . . . .160 3 Results of the Polymerization Experiments 161 4 Rate Constants and Diffusion Mechanisms 164 5 Chain Length and Conversion 165

Conclusion 166 References 166

Kinetics and Mechanisms of Anionic and Group Transfer Polymerization 171 Axel H. E. Müller, Hartwig Höcker, and Günter V. Schulz Introduction 171 Polymerization of Styrene 173

1 Ions and Ion Pairs 173 2 Contact and Solvent-Separated Ion Pairs 176

Polymerization of Acrylic Monomers 179 1 Potential Problems 179 2 Methyl Methacrylate 181 3 Other Methacrylates 191 3.1 Homopolymerization 191 3.2 Copolymerization 192 4 Polymerization in Non-Polar Solvents 194

Group Transfer Polymerization of Methacrylates 196 1 Introduction 196 2 General Considerations 197 3 Kinetic Investigations 199 4 Control of Molecular Weight Distribution 202

References 204

Contents

9 Molecular Engineering of Liquid Crystalline Polymers . .211 Helmut Ringsdorf, Ingrid Voigt-Martin, Joachim Wendorff, Renate Wüstefeld, and Rudolf Zentel

9.1 Introduction: Self Organizing Systems 211 9.2 Molecular Architecture of Liquid Crystalline Polymers . . 212 9.2.1 Liquid Crystalline Polymers with Rod-like Mesogens . . . 218 9.2.1.1 Synthesis and Structure-Property Relations of LC Side

Group Polymers 218 9.2.1.2 Synthesis and Structure-Property Relationships of Main

Chain Polymers 224 9.2.1.3 Molecular Engineering of LC-Polymers: Side Group and

Main Chain LC Systems 224 9.2.2 Liquid Crystalline Polymers with Disc-like Mesogens . . . 228 9.2.2.1 Polymers with Discotic Phases 231 9.2.2.2 Polymers with Sanidic Phases 233 9.2.3 Functionalized Liquid Crystalline Polymers 237 9.2.3.1 Dye Containing Polymers 237 9.2.3.2 Photosensitive Liquid Crystalline Polymers 238 9.2.3.3 Liquid Crystalline Elastomers 242 9.3 Molecular Architecture and Physical Properties 247 9.3.1 The Amorphous, Crystalline and Liquid Crystalline

State of Matter 247 9.3.2 Fluctuations in Liquid Crystalline Polymers 248 9.3.2.1 Defining Fluctuations 248 9.3.2.2 Kerr Relaxation Studies on Orientational Fluctuations . . 249 9.3.2.3 Small Angle X-Ray Scattering Studies on Orientational

Correlations in Side Group Polymers 252 9.3.3 High Resolution Electronmicroscopy as a Tool for

Visualizing Smectic Structures 253 9.3.3.1 Introduction 253 9.3.3.2 Sample Preparation 254 9.3.3.3 Structural Information Obtained by Electron Microscopy . 254 9.3.3.4 Image Analysis and Processing 260 9.3.3.5 Conclusion 262 9.4 References 262

10 Thermodynamics and Rheology of Polymer Solutions . . . 273 Bernhard A. Wolf

10.1 Pressure, the Neglected Variable 274 10.1.1 Thermodynamics 274 10.1.1.1 Pressure Dependence of Polymer Solubility 274 10.1.1.2 Pressure Dependence of Interaction Parameters 276 10.1.2 Viscometry 277

XI

Contents

10.1.2.1 Intrinsic Viscosities 277 10.1.2.2 Activation Volumes 278 10.2 On the Role of Chain Length 279 10.2.1 Development of Incompatibility 280 10.2.1.1 Experiments with Oligomers 280 10.2.1.2 Solubility Parameter Theory 280 10.2.2 Molecular Weight Dependence of Pair Interactions . . . . 282 10.2.2.1 Theoretical Concept 282 10.2.2.2 Experimental Results and Discussion 283 10.3 Interrelation of Thermodynamic and Rheological Properties 286 10.3.1 Flow under Different Thermodynamic Conditions . . . . 286 10.3.1.1 The Pull-along Effect 286 10.3.1.2 Thermoreversible Gelation 287 10.3.2 Phase Separation of Flowing Polymer Solutions 289 10.3.2.1 Experimental Results 289 10.3.2.2 Theory and Discussion 289 10.4 Outlook 292 10.5 References 293

11 Polymer Diffusion as Studied by Holographic Grating Techniques 295 Hans Sillescu

11.1 Introduction 295 11.2 Physical Principles and Experimental Aspects 296 11.2.1 Hologram Formation 296 11.2.2 Hologram Reading by Forced Rayleigh Scattering . . . .297 11.2.3 Analysis of Diffusion Experiments 299 11.2.4 Photo-Labeling and Sample Preparation 300 11.3 Applications 302 11.3.1 Diffusion of Polymer Chains by Reptation and other

Transport Mechanisms 302 11.3.2 Diffusion of Polymer Rings, Microgels, and Stars . . . .305 11.3.3 Diffusion of Monomer Dyes at the Glass Transition of

Amorphous Polymers 307 11.4 References 310

12 Deuteron NMR. A New Tool for Investigating Order and Dynamics in Polymers 313 Hans Wolfgang Spiess and Hans Sillescu

12.1 Introduction 313 12.2 Techniques 314 12.2.1 Dynamics 314

XII

Contents

12.2.1.1 Slow Motion and Solid Echo Spectra 314 12.2.1.2 Spin-Alignment 319 12.2.1.3 Spin Lattice Relaxation 320 12.2.1.4 Distribution of Correlation Times 321 12.2.2 Order 322 12.2.2.1 Orientational Distribution 322 12.2.2.2 Expansion in Terms of Spherical Functions 324 12.2.2.3 13C-MAS-NMR 326 12.3 Experimental Examples 329 12.3.1 Dynamics 329 12.3.1.1 Chain Motion in Linear Polyethylene 329 12.3.1.2 Molecular Motion and Mechanical Properties of

Polycarbonate 330 12.3.1.3 Molecular Motion in Interfacial Regions of Segmented

Polyurethanes 332 12.3.1.4 Motion of Mesogens in Liquid Crystalline Polymers . . . 333 12.3.1.5 Mobility of Lipid Chains in Polymer Model Membranes . .335 12.3.2 Order 337 12.3.2.1 Molecular Order in Liquid Christalline Polymers 337 12.3.2.2 Drawn Fibres of Poly(ethyleneterephthalate) (PET) . . .339 12.3.3 Overview of the 2H-NMR in Polymers 341 12.4 New Developments: Two-dimensional 2H-NMR 341 12.5 References 344

13 The Kerr Effect as Applied to the Investigation of Polymers 349 Bernd-J. Jungnickel and Joachim H. Wendorff

13.1 Introduction 349 13.2 Fundamentals 350 13.2.1 Experimental Setup and Procedure 350 13.2.2 Basic Theoretical Relations 352 13.2.3 Information Content of the Effect 356 13.3 Glassy-Amorphous Polymers 357 13.3.1 Theoretical Considerations 358 13.3.2 Experimental Investigations and Results 361 13.3.3 Discussion 364 13.4 Liquid Crystalline Polymers 365 13.4.1 Introduction: Pretransitional Effects 365 13.4.2 Kerr Effect and Order Parameter Fluctuations 366 13.4.2.1 Static Properties 366 13.4.2.2 Dynamical Properties 367 13.4.3 Kerr Effect Studies on Liquid Crystalline Side Chain

Polymers 368 13.5 References 374

XIII

Contents

14 Concentration Fluctuations and Kinetics of Phase Separation in Polymer Blends 377 Gert Strobl

14.1 Introduction 377 14.2 Theory 378 14.2.1 Phase Behaviour of Polymer Blends 378 14.2.2 Concentration Fluctuations in Thermal Equilibrium . . . . 381 14.2.3 Kinetics of Unmixing 382 14.3 Small Angle X-Ray Scattering Studies 385 14.3.1 Polystyrene/Poly(styrene-co-bromostyrene) Blends . . . . 385 14.3.2 Static Structure Factors 386 14.3.3 Relaxation after T-Jumps within the One-Phase Region . . 389 14.3.4 Kinetics of Spinodal Decomposition 393 14.4 References 395

15 Collective Dynamics in Polymeric Liquids as Measured by Quasi-elastic Light- and Neutron Scattering 397 Erhard W. Fischer, Bernd Ewen, and Gerhard Meier

15.1 The Dynamics of Density Fluctuations as Measured by Quasi-elastic Light Scattering 397

15.1.1 The Theory of Light Scattering from an Isotropic Viscoelastic Medium 397

15.1.2 The Comparison between Theory and Experiment . . . . 403 15.1.3 Data Evaluation of PCS Results 404 15.1.4 Connection between Molecular and Collective Dynamics . 406 15.1.5 Separation of Primary and Secondary Relaxation Processes

in Polymethacrylates 411 15.2 The Dynamics of Concentration Fluctuations in a

Compatible Binary Polymer Blend 414 15.3 Rayleigh-Brillouin Spectroscopy of Structurally Relaxing

Liquids 420 15.3.1 Inelastic Scattering from a Liquid Consisting of Linear

Chain Molecules 420 15.3.2 Hypersonic Relaxation in a Viscoelastic Non-polymeric

Liquid 422 15.4 Collective Fluctuations of Chain Segments in Dense Liquid

Polymer Systems as Studied by Neutron Spin Echo Spectroscopy 424

15.4.1 Neutron Spin Echo 424 15.4.2 Segmental Diffusion in Polymer Melts and Concentrated

Solutions 426 15.4.3 Unattached Polymer Chains in Permanent Networks . . . 434 15.4.4 Diffusive Motion of Cross-links 435

XIV

Contents

15.5 Conclusions 439 15.6 References 441

16 Structure and Properties of Semicrystalline Polymers . . . 445 Erhard W. Fischer, Manfred Stamm, and Ingrid G. Voigt-Martin

16.1 Introduction 445 16.2 Morphology of Semicrystalline Polymers 446 16.2.1 Comparison of Different Techniques 446 16.2.2 Small Angle X-Ray Scattering (SAXS) 446 16.2.3 Electron Microscopy (EM) 448 16.3 Chain Conformation in the Crystalline State 455 16.3.1 General Considerations 455 16.3.2 Experimental Techniques 458 16.3.3 Small Angle Neutron Scattering (SANS) 460 16.4 Crystallization and Melting 466 16.4.1 Investigation of the Crystallization and Melting Process . . 466 16.4.2 Stress Induced Crystallization 468 16.5 Blockcopolymers with Crystalline Blocks 471 16.5.1 Morphology and Models 471 16.5.2 SAXS and SANS Investigations 472 16.6 Conclusions 473 16.7 References 474

17 Chain Conformation and Local Order in Amorphous Polymers 477 Erhard W. Fischer and Ingrid G. Voigt-Martin

17.1 Introduction 477 17.2 Chain Conformation 479 17.3 Short-range Positional Order 484 17.4 Direct Structural Observation 488 17.5 Orientational Order 490 17.6 Density Fluctuations 494 17.7 References 496

18 Theory of Dense Polymer Systems 499 Kurt Binder, Kurt Kremer, Ingeborg Carmesin, and Alia Sariban

18.1 Introduction 500 18.2 Mean Field Theories of Polymer Mixtures 501 18.2.1 Spinodal Decomposition of Polymer Alloys 502

XV

Contents

18.2.2 Effects of Polydispersity and Shear 505 18.2.3 Wetting of Polymer Mixtures 508 18.3 Scaling and Computer Simulation Investigations 511 18.3.1 Phase Separation of A-chain - B-chain - Solvent Systems .512 18.3.2 Dynamics of a Polymer in a Tube: Test of the Reptation

Concept 519 18.3.3 Molecular Dynamics Simulation of a Polymer Melt . . . . 523 18.4 Conclusions 526 18.5 References 528

Appendix: Documentation of the Sonderforschungsbereich 41 . . . . 533

XVI